跟踪手指在屏幕上的位置生成音频样本并播放
【摘要】
此示例根据用户手指在屏幕的x轴方向上的位置，来选择频率并生成音频样本。
因为代码比较简单，那么话不多说，直接上代码。
public class FingerSynthesis extends Activity implements OnTouchListener{ AudioSynthesisTask audioSynth;//...
此示例根据用户手指在屏幕的x轴方向上的位置，来选择频率并生成音频样本。
因为代码比较简单，那么话不多说，直接上代码。
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public class FingerSynthesis extends Activity implements OnTouchListener
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{
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AudioSynthesisTask audioSynth;//播放音频样本的线程
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static final float BASE_FREQUENCY = 440;//基准音频频率
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float synth_frequency = BASE_FREQUENCY; // 440 Hz, 随着手指的移动会发生改变
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boolean play = false;//控制是否生成音频样本
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@Override
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public void onCreate(Bundle savedInstanceState)
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{
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super.onCreate(savedInstanceState);
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setContentView(R.layout.main);
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View mainView = this.findViewById(R.id.MainView);
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mainView.setOnTouchListener(this);
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audioSynth = new AudioSynthesisTask();
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audioSynth.execute();
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}
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@Override
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public void onPause()
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{
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super.onPause();
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play = false;
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finish();
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}
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public boolean onTouch(View v, MotionEvent event)
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{
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int action = event.getAction();
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switch (action)
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{
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case MotionEvent.ACTION_DOWN:
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play = true;//根据用户操作将play设置为true或者false
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synth_frequency = event.getX() + BASE_FREQUENCY;//跟踪用户手指的位置，做出相应的改变
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Log.v("FREQUENCY", "" + synth_frequency);
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break;
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case MotionEvent.ACTION_MOVE:
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play = true;
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synth_frequency = event.getX() + BASE_FREQUENCY;
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Log.v("FREQUENCY", "" + synth_frequency);
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break;
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case MotionEvent.ACTION_UP:
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play = false;
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break;
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case MotionEvent.ACTION_CANCEL:
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break;
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default:
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break;
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}
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return true;
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}
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private class AudioSynthesisTask extends AsyncTask<Void, Void, Void>
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{
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@Override
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protected Void doInBackground(Void... params)
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{
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final int SAMPLE_RATE = 11025;
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int minSize = AudioTrack.getMinBufferSize(SAMPLE_RATE,
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AudioFormat.CHANNEL_CONFIGURATION_MONO,
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AudioFormat.ENCODING_PCM_16BIT);
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AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
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SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO,
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AudioFormat.ENCODING_PCM_16BIT, minSize,
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AudioTrack.MODE_STREAM);
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audioTrack.play();
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short[] buffer = new short[minSize];
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float angle = 0;
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while (true)
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{
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if (play)
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{
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for (int i = 0; i < buffer.length; i++)
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{
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float angular_frequency = (float) (2 * Math.PI)
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* synth_frequency / SAMPLE_RATE;
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buffer[i] = (short) (Short.MAX_VALUE * ((float) Math
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.sin(angle)));//生成音频样本
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angle += angular_frequency;
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}
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audioTrack.write(buffer, 0, buffer.length);
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} else
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{
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try
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{
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Thread.sleep(50);
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} catch (InterruptedException e)
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{
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e.printStackTrace();
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}
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}
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}
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}
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}
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}
文章来源: panda1234lee.blog.csdn.net，作者：panda1234lee，版权归原作者所有，如需转载，请联系作者。
原文链接：panda1234lee.blog.csdn.net/article/details/8777684
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